public class Test {
    public static void main(String[] args) {
       /* 接口不能被实例化
        IUSB usb = new IUSB();*/
        Computer computer = new Computer();
        Mouse mouse = new Mouse();
        keyBoard keyBoard = new keyBoard();

        computer.open();
        System.out.println("========");
        computer.useDevice(mouse);
        System.out.println("========");
        computer.useDevice(keyBoard);
        System.out.println("========");
        computer.close();

        System.out.println("******变量public static final*******");
        System.out.println(IUSB.usb1);//可以直接通过接口名访问，说明是静态的
        //IUSB.usb2 = 200; //说明usb2具有final属性
    }

}
